With the development of the present mobile communication technologies, it is common that operators respectively construct their own mobile networks in one country or region, and even operate mobile communication services by using different standards of mobile networks, thus inter-network (including inter networks with same standard and inter networks with different standards) SMS interworking has become a key aspect in SMS service.
For the severe competition among operators with the 3G (3rd-Generation) mobile communication technologies coming, NP service, as a means to restrict monopoly, protect small and medium-sized operators, and guarantee better development of mobile communication technologies, has become a mobile communication service which must be implemented in regulations of more and more countries.
The NP service is usually divided into three types: Location Portability, Service Portability and Service Provider Portability. The present invention discusses the Service Provider Portability, which is commonly referred as the service of shifting network with the number. The service of shifting network with the number means that a user's service is provided by the network which the user newly subscribes to without changing the original number, and the user can enjoy the same supplementary services and value-added services as the other users in the newly subscribed network, where these services are not affected by the original network.
In order to realize the SMS service with the function of NP, the inter-network interworking is the key problem for implementing this service. For the implementation of interworking of inter-network SMS with the function of NP service, there are currently at least three categories of methods:
First category: the location of a mobile terminated short message service (MT-SMS) is obtained through MAP-SEND-ROUTING-INFO-FOR-SM message (shorten as SRI message below), and inter-network communication is limited within the same type of network. This category of methods are mainly implemented in a plurality of GSM MAP (Global System for Mobile Communications Mobile Application Part) based networks (in the mainstream three standards of 3G, the core networks of TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) and WCDMA (Wideband Code Division Multiple Access) are based on GSM MAP, shorten as GSM network below). But the communication between GSM networks and ANSI-41 (American National Standards Institute) based networks (e.g. the core network of CDMA2000 network is based on ANSI-41, shorten as CDMA networks below) is not easy to be realized by this category of method.
Patent application CN200810114269.7 is an example that is implemented by this category of method.
According to the characteristics of GSM MAP, this category of method sets the rule that the short message service center (SMSC) returns optional parameter, e.g. IMSI (International Mobile Subscriber Identity), after obtaining the routing from HLR (Home Location Register). The NP service only maintains ISDN (Integrated Services Digital Network) number, while IMSI number is provided by the new operator, thus the network for MT-SMS can be judged according to the segment of the IMSI number returned by the HLR. But the response to the SRI message in ANSI-41 based CDMA core network usually returns the optional parameter MIN (Mobile Identification Number), only a few networks that support protocol IS751 ream IMSI. Therefore adopting this category of method for CDMA networks to judge the destination network is not appropriate. Since the MAP parts in GSM network and CDMA network are quite different, this category of method can not achieve the interworking between a GSM network and a CDMA network.
Second category: searching the information of the home network of the destination number (e.g. NP query) is realized through a network gateway at signaling side, and messages are delivered through the gateway. Patent application CN200710090453.8 is an example.
The concept of Routing Number (RN) is introduced in this category of method, which separates the procedures of NP query and routing query (home MSC (Mobile Switching Center) query) and unifies GSM and CDMA procedures, thus facilitating the processing in the SMS gateway. In this case, NP query and inter-network interworking are achieved through the gateway, which increase cost and network load for network reforming. Meanwhile the MT-SMS is performed by being forwarded to SMSC in the destination network, so the source SMSC does not know if the message has been sent successfully or not in the end, thus the final charging accuracy can not be guaranteed.
Third category; the destination number query (e.g. NP query) and routing query are realized through SMPP (Short Message Peer to Peer) gateway, and messages are delivered through the SMPP gateway.
As for the implementation, the third category of method is similar to the second category. The only difference is that the gateway is arranged at SMPP side instead of the signaling side, and if SMSC judges that the destination number is not from the local network, it delivers messages to SMPP gateway for processing, and then SMPP gateway queries NPDB (Number Portability Database) to obtain the home network of the destination number, and directly delivers the messages to SMSC in home network for processing. This category of method is the easiest realization, but the shortcoming is the same as the second category of method, which is that inter-network charging statistics is not guaranteed.
In view of the above, the main technical problems of inter-network SMS interworking in NP function to be solved are as below:
1, the means of home network query;
2. the means of inter-network SMS delivery;
3. the means of inter-network charging.
Only if these problems are well settled, the scheme of inter-network interworking can be economical and practical, and also meet the network requirements.